Use v2 of the Confluence API

[farbodsz]

[farbodsz]

Seems like the REST API v2 currently only works with Confluence Cloud, not Confluence Server.

• Confluence Server: https://docs.atlassian.com/ConfluenceServer/rest/8.1.1/
• Confluence Cloud: https://developer.atlassian.com/cloud/confluence/rest/v2/intro/

So for now we'll hold off on adding it, but we can redo the "frontend" to make it appear as though we're interacting with the v2 API.